This invention relates generally to gas turbine engines, and more specifically to nozzle assemblies used with gas turbine engines.
At least some known gas turbine engines include a core engine having, in serial flow arrangement, a fan assembly and a high pressure compressor which compress airflow entering the engine, a combustor ignites a fuel-air mixture which is then channeled through a turbine nozzle assembly towards low and high pressure turbines which each include a plurality of rotor blades that extract rotational energy from airflow exiting the combustor.
The turbine nozzle assemblies are positioned between adjacent rows of rotor blades and channel airflow downstream towards the rotor blades. More specifically, in at least some known rotor assemblies, the turbine nozzle assemblies are radially outward from a disk spacer arm that separates adjacent rows of rotor blades. Each nozzle assembly includes a nozzle vane that is coupled to casing surrounding the rotor assembly, and extends outwardly from a inner band. An interstage seal assembly is coupled to the inner band with a nozzle flange. At least some known interstage seal assemblies include a honeycomb seal that is brazed to a backing sheet that is coupled to the nozzle flange.
During engine operation, turbine overseers may cause a rotor shaft coupled to the fan assembly to separate. The shaft separation may cause the rotor assembly to shift aftward such that the disk spacer arm may contact the seal assemblies. Over time, continued operation of the rotor assembly may cause the backing plate and/or the brazing material to cut through the disk spacer arm in an undesirable condition known as a disk burst.
To facilitate preventing disk bursts, at least some known gas turbine engines have been retrofitted by replacing the existing seal assemblies with a redesigned seal assembly that is positioned more downstream than the existing seal assemblies. Such retrofits are labor-intensive and may be costly.
In one aspect a method for fabricating a nozzle assembly for a gas turbine engine rotor assembly is provided. The rotor assembly includes at least two adjacent rows of rotor blades coupled together by a disk spacer arm. The method comprises providing a nozzle assembly that includes at least one nozzle including a vane that extends outwardly from a radially outer side of an inner band, coupling the nozzle assembly into the rotor assembly between the two adjacent rows of rotor blades, and coupling a seal assembly that includes a backing piece to the nozzle assembly such that the backing piece is substantially parallel to the rotor assembly disk spacer arm.
In another aspect, a rotor assembly for a gas turbine engine is provided. The rotor assembly includes a rotor and a nozzle assembly. The rotor assembly includes a rotor including a rotor shaft and a plurality of rows of rotor blades, wherein adjacent rows of rotor blades are coupled by a disk spacer arm. The nozzle assembly extends between adjacent rows of the plurality of rotor blades. Each nozzle assembly includes a nozzle including a vane extending outwardly from an inner band, and an interstage seal assembly. Each seal assembly is coupled to the nozzle inner band and includes a backing piece. The backing piece is substantially parallel to the disk spacer arm.
In a further aspect of the invention, a gas turbine engine comprising at least one turbine including a rotor assembly and a nozzle assembly is provided. The rotor assembly includes a rotor shaft and at least two adjacent of rows of rotor blades coupled by a disk spacer arm. The nozzle assembly is between the adjacent rows of rotor blades, and includes a nozzle including a vane extending outwardly from an inner band, and a seal sub-assembly. The seal sub-assembly includes a backing piece coupled to the nozzle inner band such that the backing piece is substantially parallel to the disk spacer arm.